The book "Text Mining and Analysis: Practical Methods, Examples, and Case Studies ... By Goutam Chakraborty, Murali Pagolu, Satish Garla" explains your question quite well. http://books.google.ca/books?id=SUKDAgAAQBAJ&pg=PT218&lpg=PT218&dq=text+rule+builder+node&source=bl&ots=GRW1z6ay_V&sig=UcTKkT5ecN1KcZs9QOEWTQ6HLqM&hl=en&sa=X&ei=kDdQU5GLDdKG2wWAsIH4DA&ved=0CFIQ6AEwCA#v=onepage&q=text%20rule%20builder%20node&f=false
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